File:Gypsum ("fishtail selenite") (22926739394).jpg
Original file (1,413 × 3,831 pixels, file size: 2.87 MB, MIME type: image/jpeg)
Captions
Summary
[edit]DescriptionGypsum ("fishtail selenite") (22926739394).jpg |
Gypsum ("fishtail selenite") (public display, Minnesota Discovery Center, Chisholm, Minnesota, USA) A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 5500 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates. The sulfate minerals all have one or more sulfate anions (SO4 -2). Gypsum is a moderately common hydrous calcium sulfate mineral (CaSO4·2H2O). Gypsum has a nonmetallic luster, is usually clearish to whitish, is soft (H≡2), and rather fragile/brittle. Gypsum has 3 cleavage planes, one of which is well developed (“one good cleavage), and the other two are not well developed (“two poor cleavages”). Broken gypsum specimens are frequently thin plates - the consequence of the one good cleavage plane. Gypsum has economic value as a mineral. It is the starting ingredient for making plaster and wallboard. The specimen shown above is a distinctive form of twinned gypsum that is nicknamed "fishtail selenite". "Selenite" is often perceived to be a macrocrystalline "variety" of gypsum, but it is not. Selenite is gypsum - it differs in no way from gypsum - it is gypsum. Use of the term "selenite" should be discouraged and is here considered an unnecessary objective junior synonym. Locality: unrecorded/undisclosed, but nearly identical specimens are known from the Naica Mine in Chihuahua State, Mexico Photo gallery of gypsum: <a href="http://www.mindat.org/gallery.php?min=1784" rel="noreferrer nofollow">www.mindat.org/gallery.php?min=1784</a> |
Date | |
Source | Gypsum ("fishtail selenite") |
Author | James St. John |
Licensing
[edit]- You are free:
- to share – to copy, distribute and transmit the work
- to remix – to adapt the work
- Under the following conditions:
- attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
This image was originally posted to Flickr by James St. John at https://flickr.com/photos/47445767@N05/22926739394 (archive). It was reviewed on 12 December 2019 by FlickreviewR 2 and was confirmed to be licensed under the terms of the cc-by-2.0. |
12 December 2019
File history
Click on a date/time to view the file as it appeared at that time.
Date/Time | Thumbnail | Dimensions | User | Comment | |
---|---|---|---|---|---|
current | 13:13, 12 December 2019 | 1,413 × 3,831 (2.87 MB) | Ser Amantio di Nicolao (talk | contribs) | Transferred from Flickr via #flickr2commons |
You cannot overwrite this file.
File usage on Commons
The following page uses this file:
Metadata
This file contains additional information such as Exif metadata which may have been added by the digital camera, scanner, or software program used to create or digitize it. If the file has been modified from its original state, some details such as the timestamp may not fully reflect those of the original file. The timestamp is only as accurate as the clock in the camera, and it may be completely wrong.
Camera manufacturer | Canon |
---|---|
Camera model | Canon PowerShot D10 |
Exposure time | 1/60 sec (0.016666666666667) |
F-number | f/8 |
ISO speed rating | 80 |
Date and time of data generation | 10:51, 11 June 2015 |
Lens focal length | 6.2 mm |
Orientation | Normal |
Horizontal resolution | 180 dpi |
Vertical resolution | 180 dpi |
Software used | Adobe Photoshop Elements 13.0 (Macintosh) |
File change date and time | 02:12, 6 December 2015 |
Y and C positioning | Centered |
Exif version | 2.21 |
Date and time of digitizing | 10:51, 11 June 2015 |
Meaning of each component |
|
APEX shutter speed | 5.9068905902692 |
APEX aperture | 6 |
APEX exposure bias | −0.66666666666667 |
Maximum land aperture | 2.9708536585366 APEX (f/2.8) |
Metering mode | Pattern |
Flash | Flash fired, compulsory flash firing, red-eye reduction mode |
Supported Flashpix version | 1 |
Color space | sRGB |
Focal plane X resolution | 16,460.904761905 |
Focal plane Y resolution | 16,483.517241379 |
Focal plane resolution unit | inches |
Sensing method | One-chip color area sensor |
File source | Digital still camera |
Custom image processing | Normal process |
Exposure mode | Manual exposure |
White balance | Auto white balance |
Digital zoom ratio | 1 |
Scene capture type | Portrait |
Lens used | 6.2-18.6 mm |
Date metadata was last modified | 19:12, 5 December 2015 |
Unique ID of original document | D93DB698B20AC1442F380786680A35A1 |